Push rod structure and method of manufacture



. Aug. 21, 1962 s. GoNDl-:K 3,050,045

PUSH ROD STRUCTURE AND METHOD OF MANUFACTURE Filed Feb. 12, 19Go 2 sheets-sheet 1 INVEN TOR. STANLEY GoNoEK BY @www ggg/f Mg/ @ML Aug. 21, 1962 s. GONDEK 3,050,045

PUSH ROD STRUCTURE AND METHOD OF MNUFACTURE Filed Feb. l2, 1960 2 Sheets-Sheet 2 Flc. 5

INVENTOR. STANLEY Go-o1 ATTORNEYS United States Patent litice 3,050,045 Patented Aug. 21, 1962 3,050,045 PUSH ROD STRUCTURE AND METHOD OF MANUFACTURE Stanley Gondek, Birmingham, Mich., assignor to .Bundy Tubing Company, Detroit, Mich., a corporation f Michigan Filed Feb. 12, 1960, Ser. No. 8,331 4 Claims. (Cl. 123-90) This invention involves push rods of the type having a rounded bearing surface adjacent one end, and having a generally radial flange which provides a seat for a coil spring utilized to hold the bearing surface in operative engagement with a rocker arm, cam follower or. other part in a mechanical train. Selected for illustratlon of the invention is a push rod in the valve train of an 1nternal combustion engine.

The object of the invention is to provide a light weight,

' inexpensive push rod structure of improved operating characteristics and a rapid, relatively inexpensive, improved method of its manufacture.

Generally the invention contemplates a tubular push rod body having an end forming a seat to which a curved surface on an end piece is welded. The end piece has a curved bearing surface disposed exteriorly of the tube and has a flange, one face of which forms an abutment for an electrode to facilitate welding, and the other face of which forms the seat for a coil spring in the valve train. One form of the invention is shown in the accompanying drawings.

FIG. l is a view partly in elevation and partly in section illustrating a push rod according to this invention in use.

FIG. 2 is an enlarged view of the push rod with portions broken away at one end to illustrate structure.

FIG. 3 is an enlarged perspective view of an end piece separate from the tube.

FIG. 4 is a fragmentary partially sectional view illustrating a step in manufacture of the push rod.

FIG. 5 is a view similar to FIG. 4 illustrating a subsequent step in manufacture of the push rod.

Shown in FG. l is a push rod according to this invention operably interconnecting a cup-shaped valve lifter 12 and a valve operating rocker 14. Lifter 12 is raised and lowered by a cam 16 on a cam shaft 1S .and the lifter moves in a guide 20 formed in an engine block 22. Rocker 14 is rockably mounted on a shaft 24 with one arm 26 operably engaged with a valve (not shown) and with another arm 28 on the opposite side of shaft 24 engaged with the push rod. Arm 28 has a projection with a spherical surface 30 engaged within a complementary spherical concavity in a cup-shaped end piece 32 at one end of the push rod.

The other end of the push rod is provided with an end piece 34 having a spherical end surface 36 bearing against a complementary spherical concave surface 38 in the bottom of cup-shaped valve lifter 12. End piece 34 has a radial ange 40, one face 42 of which forms .a seat for engagement by an end of a coil spring 44 which is compressed to bias bearing surface 36 against seat 3S. Spring 44 reacts against a retainer 46 secured by suitable means not shown to engine block 22 and having a central opening 48 through which the push rod extends.

End piece 34 has a cylindrical portion 50 extending longitudinally away from face 42 and serving as a pilot or positioning means for centering the end of coil spring 44 with respect to face 42. End piece 34 has adjacent one end a curved surface 52 which is secured to an end portion of the tubular body 54 of the rod in a manner to be described. In the form of the invention illustrated, surface 52 is convex and is provided by a conical projection 56. Flange 40 has a surface 58 which faces in a direction opposite from surface 42, and extending longitudinally from surface 58 is a cylindrical projection 60 serving a purpose to be described. End piece 34 is preferably formed of a relatively hard material such as a case hardened steel and may conveniently be formed by cold forging. By this means exposed surface 36 provides a hard smooth bearing surface for engagement with seat 38 on valve lifter 12. Surface 36 is free of any machining marks and requires minimal treatment subsequent to being forged and prior to use. End piece 34 is secured to an end of tube S4 by a fused metal connection such as by soldering, brazing or welding.

Cup-shaped end piece 32 preferably comprises .a case hardened stamped part secured to the other end of tube 54 by a fused metal connection as disclosed in copending application Serial No. 770,496, filed October )29, 1958 by Edward O. Burnard and Raymond T. Read entitled Push Rod and Method of lts Manufacture, now Patent Number 2,960,080 dated November l5, 1960.

The tubular push rod body 54 has open ends prior to the time when end pieces 32 and 34 are secured thereto. The tube may have any cross sectional shape, although the round shape illustrated is suitable for most purposes and facilitates economic manufacture. The tube may be of any suitable rigid type, such as an extruded seamless tube or a rolled plural or single ply tube and may be made of any suitable material such as ferrous metal which will give it the requisite rigidity. An example of 4a suitable tube is a single ply rolled steel tube having a butt welded longitudinal seam.

In the form of the invention illustrated, end piece 34 has been fastened to tube 54 by resistance welding. Conical surface 52 is engaged against the seat formed at an open end portion of the tube so that surface 52 and the seat engaged in a generally annular region of contact. A suitable electrode, not shown, is connected to tubular body 54. Another electrode 62 having a tubular end is engaged around cylindrical portion 60 of end piece 32 as illustrated in FIG. 4, thereby assisting in centering end piece 34 relative to the end of tube 54.

Electrode 62 and tube 54 are then advanced toward each other. End face 64 of electrode 62 engages face 58 on ange 40 and urges conical surface 52 rmly against the end of tube 54. A welding current is then passed through end piece 34 and the tube to effect the welding. During the welding, the walls defining the end of the tube are softened and end piece 34 yand tube 54 move toward each other to the general condition illustrated in FIG. 5. During this process, the walls adjacent the end of the tube are flared somewhat in a radial direction, thus increasing the width of the weld yand providing a very sturdy joint between the end piece and tube. Pillets formed during the welding are illustrated at 66 and l68.

In the form of the invention illustrated, the various surfaces of end piece 34 are substantially concentric around the longitudinal center line or axis of the end piece and the axis of the end piece coincides substantially with the longitudinal axis of tube 54. Also in the structure illustrated, cylindrical portions 50 and 60 of the end piece have different axial dimensions to facilitate hopper feeding of the end piece to a position yfor engagement between electrode 62 and tube 54.

in use, spherical bearing surface 36 is engaged within spherical seat 38 on valve lifter 12 and spherical projection 30 on rocker arm 28 is engaged within the complementary concavity in cup-shaped end piece 32. Since these interengaged surfaces are spherical, push rod 10 may have random rotative orientation about its longitudinal axis. The push rod generally is admirably adapted for interconnecting machine parts having rotary components of motion such as in the case of rocker arm 2S.

Flange 40 not only provides a face 42 forming a seat for coil spring 44 but also provides a surface 58 for abutment by electrode `62. during the welding process. End piece 34 has a ready-made bearing surface 36 obviating the necessity of expensive machining operations after its attachment to tube 54. 'The invention -facilitates inexpensive manufacture since the tubing and end piece 34 are relatively inexpensive and since the open end of the tube provides a seat for engagement with end piece 34 so that special machining or other preparation of the tube is minimized or obviated in providing the seat. The invention provides a push rod which is formed of a hollow tube and which is relatively light weight so that the efficiency of an engine or machine in which the push rod is used Will be increased.

I claim:

1. Push rod structure comprising, a tube having an end defining a seat having portions disposed at a nonperpendicular angle to the longitudinal extent of said tube, an end piece having an axial extent which is small as compared to the length of said tube, said end piece having in axial succession adjoining first, second, and third portions, said first portion providing a curved surface adjacent one end of said end piece having portions disposed at a non-penpendicular angle to the longitudinal extent of said tube and engaging said portions of said seat, said second portion having a diameter larger than the diameter of said tube, said second portion extending longitudinally away from said tube and from said first portion and terminating in a generally radial surface disposed toward said tubing, said radial surface defining a seat for a spring in a mechanism with which said push rod is adapted to be used, said longitudinally extending portion providing positioning means for a spring engaged against said seat, said third portion projecting longitudinally away from said spring seat and providing at the other end of said end piece a rounded surface portion defining a bearing surface adapted for engagement with a part of a mechanism with which said push rod is adapted to be used, and a fused metal connection connecting said curved surface of said end piece directly to said portions of said seat on said tube with said positioning means, spring seat, and bearing surface disposed exteriorly adjacent said tube end.

2. Push rod structure comprising, a tube having an end defining a seat having portions disposed at a nonperpendicular angle -to the longitudinal extent of said tube, an end piece having a longitudinal extent which is small as compared to the length of said tube, said end r piece having in longitudinal succession first, second, and third `adjoining portions, said first portion providing adjacent one end of said end piece a curved surface with portions disposed at a non-perpendicular angle to the longitudinal extent of said tube and engaging .portions p portion having a rounded surface portion longitudinally displaced from said fiange and providing adjacent the other end of said end piece a bearing surface adapted for engagement with a part of a mechanism with which said push rod is adapted to be used, and a fused metal connection connecting said curved surface on said end piece directly to said seat on said tube with said second and third end piece portions disposed exteriorly generally adjacent the tube end.

3. Push rod structure comprising, a tube having an end defining a seat having portions disposed at a nonperpendicular angle to the longitudinal extent of said tube, an end piece having a longitudinal extent which is small as compared to the length of said tube, said end piece having first, second, third, and fourth adjoining portions in axial succession from end to end, said first portion providing a curved surface engaging portions of said seat, said second portion having a diameter greater than the diameter of said tube and providing a generally cylindrical `longitudinally extending portion, said third portion defining a ange projecting outwardly from said cylindrical portion, said flange having a generally radial face disposed toward said tube and providing a seat, said cylindrical portion and seat forming respectively a positioning means and an abutment for a spring in a mechanism with which said push rod is adapted to be used, said abutment being spaced longitudinally away from said tube, said fourth portion having a rounded surface portion which is axially displaced from said frange and which provides adjacent the end of said end piece opposite from said conical surface a bearing surface adapted for engagement with a part o-f a mechanism in which said push rod is adapted to be used, and a fused metal connection connecting said curved surface of said end piece directly to said portions of said seat on said tube, with said positioning means, spring seat, and bearing surface disposed exteriorly adjacent said tube end, said curved surface, cylindrical portion, spring seat, and bearing surface being substantially concentric with the axis of said tube.

4. The combination defined in claim 3 wherein said end piece has a cylindrical portion extending between said bearing surface and said flange, said ange having a generally radial face disposed away from said tube and adjoining the -latter said cylindrical portion, said adjoining face and cylindrical portion being substantially concentric with the axis of said tube and providing respectively an abutment and positioning means for an electrode in the course of manufacture.

References Cited in the file of this patent UNITED STATES PATENTS 1,823,419 Almen Sept. 15, 1931 2,223,730 Ledig Dec. 30, 1940 2,735,313 Dickson Feb. 21, 1956 2,743,712 Hulsing May 1, 1956 2,755,368 Wirt et al. July 17, 1956 2,903,564 Carr Sept. 8, 1959 FOREIGN PATENTS 714,647 Great Britain Sept. 1, 1954 1,177,285 France Dec. 1, 1958 (Corresponding U.S. 2,975,775, March 2l, 1961.) 

